I actually considered buying frozen pinkies in bulk just because I have a huge deep freezer with very little in it as it is. I refuse to feed live ever because of the danger to my snake. Pinky is only about a month old, so I will be going on pinkies for quite a while.
A bag of 100 extra small pinkies = $35 at
www.rodentpro.com
For each size increase, the bag goes up by $5 all the way up to $65 for hairless hoppers. The larger ones vary. But that seems to be cheaper than buying them individually in the store.